Bilal ibn Rabah

Bilal ibn Rabah (580-640) was a sahabi of Muhammad and the first muezzin. A former slave like Ammar ibn Yasir, he was freed by Abu Bakr due to Islam's teachings on slavery, and he called people to prayers with a powerful voice. He lived a monastic life after Muhammad's death in 632, dying in 640.

Biography
Bilal ibn Rabah was born in 580 in Mecca, the son of an Arab slave named Rabah and a captured Abyssinian princess named Hamamah. He was a slave of Umayyah ibn Khalaf, and he was recognized as a good slave and entrusted with the keys to the idols of Arabia. Bilal would sneak away from his homestead and listen to Muhammad preach in 610, converting to Islam and telling fellow slave Ammar ibn Yasir about Islam. He was persecuted by his master, and he was nearly crushed to death under heavy rocks had it not been for Waraka ibn Nawfal's intervention. Bilal was entrusted with the treasury of Medina under Muhammad, joining him as a sahabi in the struggle with the pagan Quraysh. He also called Muslims to prayer as the first muezzin, and he fought at the Battle of Badr and other battles of early Islam. In 630, his call to prayer from the Ka'aba was the first Muslim call to prayer, and he entered a monastic life after Muhammad's death in 632. He died in 640.